Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
  • F16K3/22—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution
  • F16K3/24—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution with cylindrical valve members
  • F16K3/246—Combination of a sliding valve and a lift valve
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
  • F16K3/22—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution
  • F16K3/24—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution with cylindrical valve members
  • F16K3/243—Packings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
  • F16K3/30—Details
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/18—Sealings between relatively-moving surfaces with stuffing-boxes for elastic or plastic packings
  • F16J15/184—Tightening mechanisms
  • F16J15/185—Tightening mechanisms with continuous adjustment of the compression of the packing
  • F16J15/186—Tightening mechanisms with continuous adjustment of the compression of the packing using springs
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/26—Sealings between relatively-moving surfaces with stuffing-boxes for rigid sealing rings
  • F16J15/30—Sealings between relatively-moving surfaces with stuffing-boxes for rigid sealing rings with sealing rings made of carbon
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K25/00—Details relating to contact between valve members and seats
  • F16K25/005—Particular materials for seats or closure elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
  • F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
  • F16K3/22—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution
  • F16K3/24—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with sealing faces shaped as surfaces of solids of revolution with cylindrical valve members

Definitions

• the disclosure relates to process control valves, such as sliding stem valves, and more particularly to sliding stem control valves having a graphite/metal seal assembly for high temperature operations.
• Process control valves are used in systems or processes that require regulation or control of process fluid flows.
• Such control valves may be configured as sliding stem valves, rotary valves, globe valves, etc.
• a control element such as a valve plug
• fluid flow through the control valve may be precisely set.
• the valve plug slides or moves relative to the valve seat generally within a valve body.
• a cage may be included, the valve plug sliding within the cage. Because the valve plug slides within the valve body, preventing fluid flow between the valve plug and the valve body (or cage) is important. At the same time, reducing friction and minimizing wear and adhesion between the valve plug and the valve body (or cage) is desirable.
• a seal may be incorporated into valve plug itself, or the seal may be incorporated into the valve body (or cage) or bonnet. Regardless, the seal must prevent fluid from flowing between the valve plug and the valve body or bonnet. In an effort to both prevent fluid from flowing between the control element and the valve body or bonnet, and to reduce friction generated between the control element and valve body or bonnet, some sliding stem valves have incorporated relatively soft materials into the seal.
• Such seals are spring loaded, pressure assisted lip seals constructed from neat, filled, or reinforced polytetrafluoroethylene jackets with a corrosion resistant spring constructed from stainless steel, nickel or cobalt based alloys.
• fluoropolymers ultrahigh molecular polyethylene, and polyurethane are other jacket materials that are used.
• Other types of seals that have been used include synthetic o-rings, quad-rings, backup rings with PTFE based wear rings and metal reinforced PTFE based monolithic seals. While reducing friction and providing a high quality, resilient seal, soft materials are generally not useful in high temperature
• the graphite seal rings are able to withstand high temperatures, the graphite seal rings do not generally provide an optimum seal between the valve plug and the valve body (or cage) or bonnet because they are not flexible, compliant, or resilient.
• Graphite seal rings may be damaged from friction created between the valve plug and the valve body (or cage) and they are relatively vulnerable to particles and contaminants in the flow stream particles or contaminants that have adhered to the valve plug or valve body (or cage).
• the lack of compliance in monolithic graphite materials results in significantly more shutoff leakage than the softer rubber or plastic compliant materials that are employed in low temperature environments.
• graphite seal rings have relatively high coefficients of friction, which leads to excess friction and wear when the valve plug is moved. This excess friction and wear leads to degradation and early failure of the seal and/or the control element.
• a sliding stem control valve includes a valve body having an inlet and an outlet. The inlet and outlet are fluidly connected by a fluid flow passageway.
• a valve seat is located in the fluid flow passageway.
• a slidable control element cooperates with the valve seat to control fluid flow through the valve body.
• a seal assembly is located between the control element and the valve body.
• the seal assembly includes a metal/flexible graphite seal ring located between a first backup ring and a second backup ring.
• a biasing element is located adjacent one of the backup rings and a retainer ring maintains the biasing element adjacent the backup ring so that force generated by the biasing element is transferred to the backup ring and thus to the metal/flexible graphite sealing ring.
• a seal assembly for a high temperature sliding stem control valve includes a metal/graphite seal ring that is located between a first backup ring and a second backup ring.
• a biasing element is located adjacent the second backup ring and a retainer ring is located adjacent the biasing element.
• the metal/graphite seal ring may include a flexible graphite ring surrounded on at least three sides by a thin metal envelope.
• the seal assembly may be located in an annular recess formed in the control member. [0008] In yet another embodiment, the seal assembly may be located in an annular recess formed in the valve body.
• the disclosed seal assembly provides superior sealing capabilities in high temperature environments while reducing or minimizing friction between the control member and the valve housing.
• FIG. 1 is a cross-sectional view of sliding stem control valve constructed in accordance with the teachings of the disclosure
• FIG. 2 close up cross-sectional view of the control element of the sliding stem control valve of FIG. 1, including a metal/graphite seal assembly;
• FIG. 3 is a close up cross-sectional view of a portion of the control element including the metal/graphite seal assembly.
• FIG. 4 is a further close up cross- sectional view of the metal/graphite seal assembly of FIG. 3.
• FIG. 1 illustrates a sliding stem control valve 10 assembled in accordance with the teachings of the disclosed example of the present invention and having a valve body 12, a fluid inlet 14, a fluid outlet 16, and a passageway 18 connecting the fluid inlet 14 and the fluid outlet 16.
• a control member such as a valve plug 20, is slidably mounted within the valve body 12 and shiftable between a closed position (as shown in FIG. 1), which prevents fluid flow through the valve body 12, and an open position (not shown), which allows fluid flow through the valve body 12.
• the valve plug 20 is a balanced valve plug.
• other valve plug 20 is a balanced valve plug.
• the valve plug 20 may be unbalanced.
• the valve 10 includes a seat ring 22, which cooperates with the valve plug 20 to control fluid flow through the valve body 12.
• the control valve 10 also includes a valve stem 26 coupled to the valve plug 20 and extending through a bonnet 28.
• the valve stem 26 extends along an axis A and is connected to a valve actuator (not shown) for moving the valve plug 20 between the closed position shown in which the valve plug 20 is in contact with the seat ring 22, thereby preventing fluid flow through the passageway 18 and an open position in which the valve plug 20 is spaced away from the seat ring 22, thereby allowing fluid to flow through the passageway 18.
• a valve seal assembly 30 is located in an annular recess 32 formed in the valve plug 20, as illustrated on the left side of FIG. 2.
• the seal assembly 30 may be located in an annular recess 33 formed in the valve body 12, as illustrated on the right side of FIG. 2.
• the seal assembly 30 may include a metal/graphite seal ring 34.
• the metal/graphite seal ring 34 may include a graphite ring 36 seated within a metal envelope 37.
• the metal envelope 37 may be formed from a thin metal foil having a thickness in the range of about 0.001 in to about 0.005 in.
• the metal foil comprises a durable metal alloy such as N07718 or N07750, for example.
• the metal envelope 37 protects the graphite ring 36 from frictional damage during reciprocation of the valve plug 20.
• the metal envelope 37 may also reduce friction between the valve plug 20 and the valve body 12. For example, in other words, in other words, in other words, in other words, in other words, in other words, in other words, in other words, in other words, in other suitable metal alloy such as N07718 or N07750, for example.
• the metal envelope 37 protects the graphite ring 36 from frictional damage during reciprocation of the valve plug 20.
• the metal envelope 37 may also reduce friction between the valve plug 20 and the valve body 12.
• the metal foil may be coated with a silver plating, or the metal foil may comprise slightly softer metals, such as aluminum, copper, or bronze.
• the graphite ring 36 fits within the metal envelope 37, the metal envelope 37 surrounding the graphite ring 36 on three sides (as illustrated in cross-section in FIG. 4), while a fourth side (i.e., the upper side as illustrated in FIG. 4) remains open.
• the metal envelope 37 generally has a "U" shape in cross section including a bottom side 39, and inner side wall 41, and an outer side wall 43.
• the inner side wall 41 and the outer side wall 43 extend upward substantially perpendicular to the bottom side 39.
• the inner side wall 41 and the outer side wall 43 have heights H that are greater than a thickness T of the graphite ring 36. In other words, the inner side wall 41 and the outer side wall 43 extend above (as illustrated in FIG. 4) the graphite ring 36.
• the metal/graphite seal ring 34 may be located between a first backup ring 60 and a second backup ring 62.
• the first and second backup rings 60, 62 may be formed of any hardenable material, such as S41600 stainless steel, for example.
• the first and second backup rings 60, 62 maintain proper positioning of the metal/graphite seal ring 34 within the annular recess 32 (or the annular recess 33) as well as providing anti-extrusion protection for the metal/graphite seal ring 34.
• the first and second backup rings 60, 62 also protect the metal/graphite seal ring 34 from environmental factors, such as excessive heat and pressure.
• the second backup ring 62 is positioned at least partially within the metal envelope 37. As a result, the second backup ring 62 has a smaller radial dimension than the first backup ring 60.
• a biasing element 64 such as a Belleville spring, a spiral wound gasket, or a bolted cap, for example, may be located adjacent the second backup ring 62.
• the biasing element 64 applies axial force to the second backup ring 62, which is transferred to the graphite ring 36.
• This axial force causes the graphite ring 36 to expand radially outward as the graphite ring 36 is compressed between the first backup ring 60 and the second backup ring 62.
• the graphite ring 36 expands radially outward, the graphite ring 36 pushes the metal envelope 37 against the valve body 12, which produces an excellent fluid seal between the seal assembly 30 and the valve body 12.
• a retainer ring 70 retains the biasing element 64 in position against the second backup ring 62.
• the retainer ring 70 may be at least partially located in an annular slot 72 formed in the control element 20.
• the retainer ring may be at least partially located in an annular slot in the valve body 12. The retainer ring 70 prevents the biasing element 64 from becoming separated from the second backup ring 62.
• a seal assembly that provides superior sealing capability, while reducing friction between a control member and a valve body, for high temperature control valves.
• a graphite ring By enveloping a graphite ring at least partially within a metal envelope, the graphite seal ring is protected from friction and environmental factors while providing an excellent fluid seal.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Lift Valve (AREA)
• Sliding Valves (AREA)
• Details Of Valves (AREA)
• Sealing Devices (AREA)

Priority Applications (9)

Applications Claiming Priority (2)

Publications (1)

Family

ID=50555270

Family Applications (1)

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Cited By (1)

Families Citing this family (6)

Citations (8)

Family Cites Families (18)

• 2014
  • 2014-03-12 CN CN201420233895.9U patent/CN203857065U/zh not_active Expired - Lifetime
  • 2014-03-12 CN CN201410192580.9A patent/CN104048060B/zh active Active
  • 2014-03-13 EP EP14719576.2A patent/EP2971885B1/en active Active
  • 2014-03-13 KR KR1020157024520A patent/KR102202199B1/ko active IP Right Grant
  • 2014-03-13 JP JP2016502023A patent/JP6336030B2/ja not_active Expired - Fee Related
  • 2014-03-13 WO PCT/US2014/026005 patent/WO2014151564A1/en active Application Filing
  • 2014-03-13 CA CA2902044A patent/CA2902044C/en active Active
  • 2014-03-13 US US14/208,389 patent/US9360128B2/en active Active
  • 2014-03-13 RU RU2015140472A patent/RU2665801C2/ru active
  • 2014-03-13 MX MX2015012123A patent/MX364416B/es active IP Right Grant
  • 2014-03-13 BR BR112015021952A patent/BR112015021952A2/pt not_active IP Right Cessation
  • 2014-03-13 AU AU2014233914A patent/AU2014233914B2/en not_active Ceased
  • 2014-03-14 AR ARP140101022A patent/AR095320A1/es unknown
• 2015
  • 2015-09-02 NO NO20151114A patent/NO343194B1/en not_active IP Right Cessation

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